LONDON— When Suzie Pell awoke Thursday morning, she was excited and nervous.

The 24-year-old Pell was a newly-minted art history major, bound for Lloyd’s of London, the prestigious insurance firm. She was hoping to be hired by the department that insures fine art.

“I got up really early, and was sort of taking really great care over my appearance,” says Pell. “I put on my suit, all very simple, being very grown up. My brother teasing me, ‘Little sister, all dressed up and going to work.’ He couldn’t get over the sight of me looking so grown up.”

She even borrowed her mother’s cream pashmina scarf.

“I gave her a big hug and said ‘Let’s hope it’s a good day,” said Suzie's mom. “I didn’t really see what was ahead of us.”

Someone was saying to me ‘Are you ok? Are you ok?’ And I guess I sort of came to and then the smoke started to clear.

People could sort of start to make out figures, and someone saw that I was bleeding and handed me a tissue. So I sort of patted my head. Of course, you take it away and see the blood which is always very alarming. It sounds such a cliché but it was like being in a movie.

Suzie then did something remarkable — instead of turning away from the blasted car next to her, she turned toward it.

Phillips: So when you looked into the car behind you what did you see?

Pell: People were crying out for medics, and for people who knew first aid, and doctors. I just felt so helpless. I was hearing people cry out. I thought there must be something I can do. So I got past obstacles and got just into that other carriage.

Phillips: So you left your car and went into the one behind you?

Pell: Yup. I heard people, so I went into the car. I saw dead bodies, people who’d had their clothes blown off them, mangled metal and bodies. I couldn’t see halfway down the carriage. I just heard people crying out.

I helped the people I could directly access — one person had a broken leg, and he was screaming out for help, that’s the person I’d heard. You could see lots of lacerations in his leg, huge gapes in the skin, but I’m not a doctor so I presumed it’s badly damaged.

He was saying “What do I do?” He was really panicky really terrified. He said “I’m bleeding I’m bleeding, got to stop the bleeding what should I do, anyone know, anyone can help?”

I knew enough of the basics of first aid just from general common sense: I had to elevate it. The leg was covered with mangled metal so I had to lift off the metal and he was screaming out in pain. I had to elevate it but there was no place to put it apart from on the lap of the person next to him.

Phillips: And for the bleeding?

Susie: I had a cream scarf, so I tied that and got it lashed around the top of his leg.

Pell: Exactly. I tried to stop the bleeding and tried to make him stable and he was so panicky. And I tried to calm him. I guess I was fibbing slightly, but just saying, “It’s okay, it’s just a cut you’re fine. Yes you’re bleeding, try and keep still.” Just trying to calm him down.

I said “You’re going to be okay,” but I didn’t really know if we were going to be ok.

Then Pell says word came from the driver that passengers should walk through the cars to the front of the train. Suzie helped lead two of her fellow survivors — staggering and in shock — out and onto the track. There, everyone waited in a dark and airless tunnel for what she says seemed like half an hour.

Pell: We could hear the cries of the people and see the bodies. The driver says “Don’t look, but of course you do.”

We were stuck in a tunnel, helping a big strong guy with glass injuries, holding his hand trying to soothe him, telling him “you’re gonna be okay.”

Even after rescue workers finally made it to the train, the ordeal was not over. Pell helped guide an injured rider on a harrowing 200-yard walk, along side tracks that were still electrified in places, back into the subway station, and to safety.

Phillips: When did you finally exhale?

Pell: I guess, when I came out and saw the normality of my tube station and Marks & Spencer, realizing daylight, and knowing I was out. That’s when I burst into tears.

Pell went to a local hospital where she was treated for what turned out to be remarkably minor wounds.

But many were not as lucky as she: In all, seven passengers on her train were killed.

Pell has also probably seen the last of that business suit she was wearing. At Scotland Yard’s request, she put it in a plastic evidence bag, bound for a crime lab. Residue on the dress will be tested for possible clues about the bombing.

Dateline wires the home of a volunteer, Jenny, from top to bottom with hidden cameras. Then she called repairmen to her house for a simple problem we created as a test with Jenny's pool. NBC's Chris Hansen reports.